The Westminster dog show, at Madison Square Garden in New York, hasn't only been about the dogs lately. Last year, PETA protesters invaded the two-day event.

As a handler in one of the fantastically dowdy suits that are a Westminster hallmark trotted a graceful Doberman around the ring, one of the protesters held up a sign reading "Mutts rule."

She was led away by blue-suited security officers, but another protester appeared, smartly dressed in jacket and slacks, and mounted the winners podium to hold up a sign that read "Breeders Kill Shelter Dogs Chances." Her message lasted for maybe 10 seconds before she too was led away.

The protests are an indication of how complicated dog politics have become. To start with, these days, mutts do rule, at least relatively. Rescue dogs, which are mostly mutts, have never been more popular, while the American Kennel Club, arbiter and protector of purebred dogs, has seen its membership and registrations drop for a decade or more. The AKC brand has been partly hollowed out: Purebred used to mean excellent; now it can as easily mean inbred.

People for the Ethical Treatment of Animals, though inspired by the horror of shelters in 1970s America, is in many ways a latecomer to these issues. PETA's founder and head, Ingrid Newkirk, as the young expatriate bride of a race car driver, volunteered at an animal shelter and was appalled at the conditions in which the animals lived and died.

It opened her eyes to animal suffering. Alarmed at the carelessness of her co-workers, she volunteered for extra euthanasias, and eventually founded an organization that's done more than any other to change the way we view the treatment of animals.

Frank Franklin Ii, Associated Press

A Bichon Frise rests before competing in the The Westminster Kennel Club Dog Show Monday, Feb. 11, 2013, at Madison Square Garden in New York.

It's an amazing legacy but a complicated one. In the past, PETA viewed the keeping of household pets as equivalent to chattel slavery. "If people want toys, they should buy inanimate objects," Newkirk said years ago.

These days, those kinds of sentiments have been deeply submerged, if they still exist at all in PETA. Newkirk herself became much cuddlier, even writing a book called "Let's Have a Dog Party," possibly because she's realized that it's difficult for a broad-based animal rights organization to survive without the donations of pet owners.

But even with this adjustment, PETA's radicalism can be grating and off-key. In recent years, it has equated the AKC with the KKK - because of both organizations' emphasis on purity - and sent protesters to Westminster in hooded robes.

PETA's point is that, with homeless dogs languishing in shelters, more dogs shouldn't be purposely brought into the world - a notion that contains a sensible kernel but is precisely the kind of stern moral equation ("A pig is a dog is a rat is a boy" was the organization's motto a decade ago) that makes it difficult for most people to buy into PETA's message.

PETA aims to reduce animal suffering by any means necessary; it's utilitarian mathematics. And the most shocking consequence of this aim is that PETA euthanizes a remarkably high percentage of the animals it rescues: more than 90 percent in 2011.

One would expect in an animal rights organization more of a distinction between life and death, even painless death, but PETA has always talked in remarkably positive terms about euthanasia. Years ago, Newkirk called euthanizers "dark angels." Just last year, a PETA spokesperson told a reporter that euthanasia was "a product of love for animals who have no one to love them."

Attitudes like this make PETA and the no-kill movement - natural allies in their fight against the AKC - into the bitterest of enemies. For the no-kill movement, an animal life is a life, and that life itself is what's important, not just the suffering.

Though there are still too many dogs in U.S. shelters, and too many of them end up euthanized, the no-kill movement has actually been a huge success story, reducing euthanasias in shelters by a factor of four while creating a vast, ad hoc national network devoted to saving dogs.

The results - rescue dogs - tend to flow from Southern and heartland red states, where leash laws and spay-neuter provisions are generally laxer and the old farmyard animal ethics still hold sway, to blue states, where in many suburbs there aren't enough rescue dogs, especially puppies, to meet the demand.

Care must be taken that the current system isn't commercialized. (And, given the speed of change in the dog world in the last few decades, the current system probably won't last.)

Westminster, with its air of tradition and its aspirations to be the Super Bowl of dogs, seems a perfect place to protest the dog status quo - and of course, there's much to protest. But in many ways the dog status quo has already changed - and Westminster is a kind of relic.

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John Homans, executive editor of New York magazine, is the author of "What's a Dog For: The Surprising History, Science, Philosophy and Politics of Man's Best Friend." He wrote this for the Los Angeles Times.